8. Jim Walton

• Net Worth: $23.7 B                                                                 
• Source of Wealth: Wal-Mart, inherited
• Citizen: United States
• Age: 65

Jim is the youngest son of retail visionary Sam (d. 1992), who founded the massive retailer with his brother James, opening a single store in Rogers, Ark. in 1962. Wal-Mart -- which is up 5% from last year -- now has sales of nearly $470 billion and employs 2.2 million people in 11,000 stores worldwide. Jim has received more than $350 million in dividends after taxes in 2013. He is also the CEO of the Walton family's Arvest Bank, which has branches in Arkansas, Kansas, Oklahoma and Missouri. The bank is worth about $1.8 billion, with net profits of nearly $100 million in 2012.